Rolling mill structures



March 29, 1966 T. A. FOX

ROLLING MILL STRUCTURES Filed June 28, 1961 s on J l 2 l, Q T ON I t w w om E I L om O z INVENTOR Thomas A. Fox

United States Patent 3,242,711 ROLLING MILL STRUCTURES Thomas A. Fox, Youngstown, Ohio, assignor to Fox Industries, Inc., a corporation of Ohio Filed June 28, 1961, Ser. No. 120,350 2 Claims. (Cl. 72-243) This invention relates to rolling mill structures and particularly to a rolling mill having a constant dimension pass line. The rolling of metal strip has a long history. It has been faced with many problems, some of which have been solved, but some of which have remained unsolved throughout the entire history of rolling. One of the most troublesome problems in strip rolling is the problem of maintaining end to end gauge of the strip. Strip bar or plate, particularly hot rolled material which has been passed through conventional rolling mill apparatus has a lead end which is undergauge corresponding to the entering end to the strip and a tail end which is an overgauge corresponding to the last portion leaving the mill. This condition is undesirable because of substantial portion of both the lead end and the tail end of the strip are out of gauge. It is also possible that the strip may be out of gauge intermediate these ends because of hard spots or the like. No mill, to my knowl edge, has ever been able to eliminate these problems.

I have invented a rolling mill structure which essentially eliminates this out-of-gauge condition and is capable of maintaining gauge in the strip or the like to very low tolerances through its entire length. My invention eliminates the effects of housing stretch on close gauge rolling and reduces mill structure deformation eifects on strip gauge to a degree never before attained on a rolling mill. Preferably I provide a pair of work rolls on opposite sides of a path of strip bar on plate travel, each of said work rolls being mounted in chocks, adjustable limit means maintaining said chocks a pre-selected distance apart and constant pressure means acting on said chocks urging them together at a pressure in excess of any pressure likely to be developed between the work rolls. Preferably the constant pressure means is a free flowing volume of fluid under regulated pressure acting by means of a hydraulic cylinder acting on the chocks urging them toward the strip.

Preferably in a four high mill, back-up rolls are provided acting on each work roll and the limit means are placed between the back-up roll chocks with the work rolls freely movable therebetween. The constant pressure means acts on the back-up roll chocks to maintain them against the limit stops at all times.

In the foregoing general statement of my invention I have set out certain objects, advantages, and purposes. Other objects, advantages, and purposes will be apparent from a consideration of the following description and the accompanying drawings in which FIGURE 1 is an end elevation of a rolling mill housing end rolls according to my invention; and

FIGURE 2 is an en elevation of a second embodiment according to my invention.

Referring to the drawings I have illustrated a housing having a window 11 carrying lower back-up roll chocks 12 and upper back-up roll chocks 13 each carrying a back-up roll 14. Work roll chocks 15 and 16 are provided beneath the back-up roll chocks 12 and 13 and independently movable with respect thereto. Wedge (or screw) spacing or limiting means 17 are provided between the back-up roll chocks to adjustably position the chocks apart a preselected distance. The wedges 17 may be moved with respect to each other by any of the conventional and well known means such as screws, hydraulic cylinders or the like. A hydraulic cylinder 18 is provided in the housing window 11 acting on the uppermost back-up roll chock 13 to urge it towards the lowermost chock 12. A constant high pressure is supplied to the piston 18 from a source of hydraulic fluid (not shown) through a constant pressure valve 19. The pressure maintained in piston 18 is higher than any pressure anticipated between the work rolls 20.

In operation the wedges 17 are set to hold the chocks 12 and 13 apart of fixed distance. A constant hydraulic pressure from a free flowing volume of fluid is applied on the cylinder 18 urging the back-up rolls together through the chocks 12 and 13 against wedges 17. The work rolls 20 are free to move between the back-up rolls. A strip to be rolled is fed into the nip between the work rolls which are immediately forced outwardly against the back-up rolls. The wedges 17 set the gap between the work rolls so that they immediately start to roll on gauge. Since the pressure 18 in the piston exceeds any pressure anticipated on the work rolls, the housing 10 is already under strain so that there is no variation on the load acting on the strip. As the strip moves through the mill, constant pressure on the piston 18 acts to maintain constant gauge, even when hard spots are found in the strip, because the stretching or elongation of the housing is taken up in the cylinder 18.

In the embodiment illustrated in FIGURE 2, I have shown hydraulic cylinders 30 between each of the back-up roll chocks and its adjacent work roll chock. By applying pressure to the work roll chocks, I am able to obtain gauge control from edge to edge as well as from end to end. The operation of the cylinders 30 is described in my co-pending application Serial No. 668,989, filed July 1, 1957, now US. Patent No. 3,024,679. This structure allows the present mill to serve a dual purpose of end to end as well as center to edge gauge control.

While I have illustrated and described certain embodiments and practices of my invention it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

1. A rolling mill structure comprising a pair of work rolls on opposite sides of a path of strip travel, a backup roll acting on each work roll, adjustable limit means between the back-up rolls positively limiting the minimum space between the back-up rolls, said work rolls being free to move between the back-up rolls, pressure means acting between the ends of the work rolls and the adjacent back-up roll with a strip to be rolled as a fulcrum to bend the work rolls around the strip to change the contour of the work rolls, and an extensible constant pressure means acting on said back-up rolls urging them toward the limit means at a pressure in excess of the working pressure between work rolls.

2. A rolling mill structure as claimed in claim 1 where- Patented Mar. 29, 1966.

3 4 in the pressure means acting on the work rolls ends are FOREIGN PATENTS hydraullc cyllnders- 900,534 10/1944 France.

References Cited by the Examiner gig? Bntam' UNITED ST E PATENTS 5 137,260 9/1952 Switzerland.

5 1 07 4 1 97 Mfelme 8Q 56 3 X CHARLES W. LANHAM, Primary Examiner. 2,430,410 11/1947 Pauls 8 56-3 WILLIAM W. DYER, JR., WILLIAM J. STEPHENSON, 2,611,150 9/1952 Goulding 8056.3 Examiners. 2,673,480 3/1954 Wellman 80-563 10 E. D. OCONNOR, C. H. HITTSON,

3,097,549 7/1963 Hudson 80--60 Assistant Examiners. 

1. A ROLLING MILL STRUCTURE COMPRISING A PAIR OF WORK ROLLS ON OPPOSITE SIDES OF A PATH OF STRIP TRAVEL A BACKUP ROLL ACTING ON EACH WORK ROLL, ADJUSTABLE LIMIT MEANS BETWEEN THE BACK-UP ROLLS POSITIVELY LIMITING THE MINIMUM SPACE BETWEEN THE BACK-UP ROLLS, SAID WORK ROLLS BEING FREE TO MOVE BETWEEN THE BACK-UP ROLLS, PRESSURE MEANS ACTING BETWEEN THE ENDS OF THE WORK ROLLS AND THE ADJACENT BACK-UP ROLL WITH A STRIP TO BE ROLLED AS A FULCRUM TO BEND THE WORK ROLLS AROUND THE STRIP TO CHANGE THE CONTOUR OF THE WORK ROLLS, AND AN EXTENSIBLE CONSTANT PRESSURE MEANS ACTING ON SAID BACK-UP ROLLS URGING THEM TOWARD THE LIMIT MEANS AT A PRESSURE IN EXCESS OF THE WORKING PRESSURE BETWEEN WORK ROLLS. 